*** DISCLAIMER ***
I work on projects that may brick your device. Don't sue me, hate me or try and kill my dog if that happens. I will feel bad the community will feel bad and hopefully we'll find a way to get you going again. But, the very nature of my projects involves a certain amount of risk taken by YOU. And by using the projects that I work on, you've accepted that fact.

WARNING #1: CURRENTLY THERE IS AN UNKNOWN ISSUE WHERE IF YOU HAVE ENCRYPTION ENABLED AND INSTALL SS IT BOOTLOOPS. IF YOU FIT THIS DESCRIPTION PLEASE STAY AWAY FROM SAFESTRAP FOR NOW.

Safestrap is a Bootstrap / Recovery for locked bootloader phones. The goal is to avoid touching your primary system (I'll call this "stock" system) and only flash or make large changes to another place on your phone that Safestrap treats as a "2nd system" (in this case, it's a series of virtual ROM slots located on the internal emmc area: "/sdcard"). Once installed, you will see a "Splashscreen" giving you the option to hit "menu" to enter recovery. The recovery portion of Safestrap is now based on TWRP 2.6.3.0 (a touch based recovery) and you can perform .zip installs, backups and restores here. The additional features I've added to TWRP are mostly located under the "Boot Options" menu:

Here you can create virtual ROM-slots (2 on the S4 due to partition size and internal space) for flashing ROMs. These ROM-slots allow for 3 different sizes of /data partitions: 1GB, 2GB and 3GB. NOTE: The bigger you make the /data partition the less room you will have to make other ROM-slots.

You can activate a new ROM-slot by choosing the slot you wish to make active and then selecting the "Activate" button. Once active, you will see the "rom-slot#" up in the top of the screen shown in green. If you make the "stock" ROM active, then you can see it in the top shown in red.

Once a ROM-slot is active, all actions you would normally perform using TWRP are directed to that ROM-slot. For example, "Install" to flash a .zip, backup and restore.

Find the APK using a Filemanager tool and open it on your device, then click "Install".

(If updating from an existing Safestrap you might be warned that this will over-write the existing installation. Click the "Yes" equivalent to this message.)

Once installed, open up the Safestrap application as you would any other app.

Agree to the disclaimer that you won't try to sue me and hunt me down with a rifle if you manage to break your phone..

Then use the "Install Recovery" button. You should see the current version down in the lower left corner of the window. And the "Status:" should say "Installed" when you're done.

From there you can reboot and you *should* see a new splash screen during the boot up. While this is showing you can enter Safestrap Recovery using the [ menu ] button.

That's it for the installation! Read below for a brief overview of Safestrap Recovery v3.x

HOW DO I ENTER RECOVERY?

During each reboot a splashscreen will be displayed showing whether the device is running a rom-slot or on the "Stock ROM".
Press under the button shown on the screen to either enter "RECOVERY" or "CONTINUE" booting.
By "under", I mean on the touch key portion of the front display on either side of the center button.

HOW DO I UPGRADE SAFESTRAP?

Push the APK up to your sdcard.

Boot back into the "stock" rom-slot.

Go into your old Safestrap app and use the "Uninstall Recovery" button

THEN, open a "file explorer" of some sort (even TW "My Files" will work)

Browse to where you pushed the APK

Click on it and install like normal

Once installed, open the APK

Grant SU access

Use the "Install Recovery" button

All set, now you can reboot and re-activate whatever rom-slot you were using

KNOWN ISSUES:

[v3.72] ROM-SLOTs aren't supported yet

[v3.72] "Reboot Recovery" doesn't work in the APK?

NEW TO v3.72:

TWRP 2.7.0.x update for the base recovery. This includes vibration support, backup time/date fixes and more.

ROM-SLOTs now have a 16gb size limit (vs 4gb previously) [THEY DON'T WORK YET IN KK THO SO BE PATIENT]

DOWNLOADS:CONFIRM THAT YOU ARE USING AN AT&T SAMSUNG GALAXY S4 (NOT THE ACTIVE MODEL)

MAKE SURE IF YOU ARE UPGRADING TO v3.7x FROM v3.65 THAT YOU USE THE "UNINSTALL RECOVERY" BUTTON IN THE v3.65 APK BEFORE INSTALLING v3.7x.

NOTE: USE ONLY ROMS THAT MATCH UP WITH YOUR TOUCHWIZ VERSION. IF YOU'RE ON MK2 THEN ONLY USE ROMS BASED ON MK2 AND IF YOU'RE ON MF3 ONLY USE ROMS BASED ON MF3

FIND YOUR STOCK OPERATING SYSTEM VERSION BELOW AND USE THAT FILENAME:

FOR USERS OF NB1:
USE 3.72+:BETA Safestrap-JFLTE-3.72.apk (updated 2014-04-02)

FOR USERS OF MK2:
USE 3.71+:BETA Safestrap-JFLTEATT-3.71.apk (updated 2013-12-27)

As of version 3.6x, Safestrap Recovery is now based on TWRP 2.6.3.x. For more on TWRP you can visit their website: http://www.teamw.in/

WARNING: Safestrap is heavily modified to be "Safe" for your device. Do not download TWRP from their website and expect it to work the same way. Also TWRP does not support Safestrap, tho some issues that may come up will be TWRP dependant, please try and contact myself or look on the forums for your device for answers before hunting down TWRP people. They won't be able to help w/ Safestrap specific questions.

This thread is a development ONLY thread.
For discussion go here:
http://forum.xda-developers.com/showthread.php?t=2428254

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